To the weak I became weak, to win the weak. I have become all things to all people so that by all possible means I might save some. 23 I do all this for the sake of the gospel, that I may share in its blessings. (I Corinthians 9:22-23 NIV)
In this verse Paul explains that he will do anything possible to try to relate to other believers and win them for Christ. However, he would not try to do the impossible by breaking the law of God in order to win others to Christ (see verse 22). He would do nothing immoral.
But one thing Paul would do, is become weak in order to win the weak. This means that he was willing to reach the simple-minded on their own level; he was willing to let go of his intellectual gifts some times, and share his faith on a more primitive level. Sadly, many Christians today refuse to do this. They will ONLY discuss their faith with other intellectuals. They despise their brothers and sisters in Christ who have a more simpler understanding of theology. This is wrong. This is not how the Apostle Paul behaved, and he was perhaps the greatest theologian of all time.